Ambae's Manaro volcano was upgraded to level four activity five days ago with the Geohazards Department warning of flying rocks, volcanic gas, acid rain and ash falls.
RNZI rpeort the coordinator for the Vanuatu Redcross Dickenson Tevi said shipping vessels were on standby awaiting the decision.
He said it was likely Ambae's population of 10,000 will be evacuated to neighbouring islands including Santo, Pentecost and Malekula.
